Automatic combustion-controlling device



May 21, 1929.

4 Shets-Sheet. 1

Filed Nov. 4, 1924 May 21, 1929. w. H. LARKIN, JR

AUTOMATIC COMBUSTION CONTROLLING DEVICE Filed Nov. 4, 1924 I72 denier:142a.

4 Sheetfiheet 2 /fiornya.

y 21, 1929. w. H. LARKIN, JR 1. 13.839 4 AUTOMATIC COMBUSTIONCONTROLLING DEVICE Filed Nov. 4, 1924 4 Sheets-Sheet 5' y 21, 1929. w.H; LARKIN, JR 1,713,839

AUTOMATIC COMBUSTION CONTROLLING DEVICE Filed Nov. 4, 1924 4Sheets-Sheet 4 May 221%, i929 a P '1 ii We: r; n in but iii ti at l hisWILLIAM H.

LAEKIN, JR, OF EASSAIG, NEVT JEBSEY, A$SIGNOB OF ONE-HALF TO ERNEST L.W'UDLLEY, OF PROVIDENCE, RHODE ISLAND.

AUTOMATIC GSMBUEiTION-CDNTROLLING DEVICE.

Application filed November This invention relates to an improvedautomatic control-device for regulating combustion in steam-boilerfurnaces.

The principal object of the invention s to provide an apparatus of thetype specified which is extremely sensitive and instantly responsive tovariations in steam pressure and steam flow to regulate combustion inaccordance with requirements with minimum consumption of fuel.

A particular object of the invention is to provide acombustioncontrolling device which is influenced by the factors of bothsteam pressure and steam flow to respond more quickly to changingconditions of steam generation and steam consumption, whereby to preventloss of pressure in the boiler without increasing combustion to awasteful degree.

Another object of the invention is to provide a control-device which maybe employed to regulate the fuel supply, the induced and iiorced draftin the furnace and other controls if required.

Further objects of the improvement are set forth in the followingspecification which describes a preferred embodiment of the invention asillustrated in the accompanying drawings. In the drawings:

Fig. 1 is a general view of a steam-boiler furnace oi. conventional typeshowing my improved control-device as applied to use therewith forregulating the fuel supply from an automatic stoker and also forcontrollng the forced and induced draft therein; i

Fig. 2 is a vertical sectional view of the control-device Fig. 3 afragmentary sectional view illustrating a modified form of one of thecontrol-clements of the apparatus;

Fig. 4 is a plan view of the control-device shown. with its casing insection to illustrate the operating parts therein;

Fig. 5 is an enlarged detailed view of the diil'erential-wcightcompcheating-mechanism which connects two of the control-elements of theapparatus;

Fig. 6 is a plan view of the same;

Fig. 7 a still further enlarged view showing a detail of theconstruction of the differential-Weight mechanism;

8 an enlarged longitudinal sectional View of the main steam pipe leadingfrom the boiler, illustrating a usual form of 4, 1924. Serial No.747,802.

Pitot tube which may be used as the steam flow element of the control;

Fig. 9 is a cross-sectional View of the main steam pipe showing thePitot tube; and

Fig. 1.0 is a longitudinal sectional view of the main steam pipe showingan orifice plate applied thereto as an alternative form of flow-controlelement.

Referring to the drawings, my improved control-device comprises aplurality of coordinated mechanisms which will first be described indetail as separate units. The several units of the apparatus arepreterablyv enclosed in a casing C herein illustrated as a rectangularbox supported from a flanged base and provided on the front with anopening or door (Z.

1l[0t07'.The motor or actuator M which furnishes the power for operatingthe fun nace controls may be of any suitable type, and I have hereinillustrated a fluid-pressure cylinder 2 containing a sliding pistonwhich may be operated by compressed air, oil or steam-pressure takendirect from the boiler. As shown in Fig. 2 the cylinder 2 is lined witha bushing 8, preferably constructed of brass or bronze, within which isthe sliding piston 4. The'piston-rod slides through a suitable gland orstui'iing box 6 at the top of the cylinder 2 and is braced by a bearingon an arm 7 extending from the upper wall of the casing Q. As indicatedin Fig. 1, the upper end of the piston-rod 5 projects through an openingin the top of the casing C and is connected to the various controls ofthe furnace, to be later described, by means of chains or cords. In somecases the piston-rod may be extended downwardly through a gland at thebottom of the cylinder 2 to project below the easing C "for connectionwith controls at a lower level, when so required.

fit one side of the cylinder 2 is a slidevalve 10 for controlling theadmission of pressure through two ports 12 and 13 in the valve-casing orsteam-chest 14, the ports communicating with the opposite ends of thecylinder through ducts l5 and 16. It will be noted that the valve-casing14 is shown in l as being offset to the front of the cylinder 2, but torender the showing of Fig. 1 clearer I have here illustrated it as beingin the vertical plane on which the section-is taken through the axis ofthe cylinder.

1 rockable lever The lever 25 has a pintube or cylinder 40 fits.

sure in the cylinder.

communicate respectively with the ports 12 and '13. The valve iscontrolled by a valve-gear V which operates on the well known principleof the trick valve employcd quite generally with mechanisms used forreversing marine engines by steam power. The valve-rod 21 extendsupwardly through a stuflingbox QQ-and at its upper end carries a forkedjoint 23 by means of which it is pivotally connected at 24 to a and-slotconnection'27 with a slidable piston 26 to be later described. At itsopposite end the lever is pivotally connected at 29 toa reach-rod 30which is joined at its upper end to a second rockable lever 3 The lever32 is fulcrumed at 33 on a fixed bearing 34 extending, from the side ofthe easing,- G. -The long arm of the lever 82 has a fork at its endformed with slots 35 which are engaged by a cross pin 36 projecting fromthe sides ofa collar 37 fast on the piston-rod 5. The reach-rod 30 ispreferably made in two parts which are connected by aturnbuckle 31 toprovide for adjusting the-length of said rod. It will be obvious thatthrough the above arrangement of the valve-gear V the valve 10 iscontrolled in position from the sliding action of the piston 26 underthe further control of the piston-rod 5 in the cylinder 2. Static, steampressure cylimleva-The piston 26 is operated under direct steam presr'sure in a relatively small cylinder. 40 constructed in the form of atube. The pressure cylinder v4O is supported vertically from a step orpedestal 41 secured to the base of the casing C and having a bore intowhich the The pedestal 41 is provided with a duct or opening 42 on itsside into which is fitted a suitable nipple connecting with the steamsupply pipe robe later described. 7 througl'i the lower end of thecylinder or tube 40 in line with the duct 42 admits steam pressure intothe cylinder from the nipple or steam pipe 43.

The piston 26 is enlarged at its lower end and bored to adapt it toenclose the steam cylinder or tube 40 so that the pressure in saidcylinder will act to raise the piston in the manner as hereinafter morefully described. At the lower end of the piston 26 is a flange 44 whichsupports a cylindrical weight 45 surrounding the piston and acting as acomiterbalance against the steam pres- The weight45 is held from turningon the piston 26' by means of ascre'w 46, and the weight and piston areprevented from turning by means of a guidescrew 47 inserted through theside of the casing C with its end engaging a slot or A small holedrilled pressure device P above described consti- V tutesthe staticpressure control-element of the apparatus and is connected by adifferontialmechanism to the steam flow control" element of theapparatus which is next described.

Steam flow contraZ-eZeme'nt. The steam flow control-clement of theapparatus con, sists of a slidable piston controlled in position underpressure from opposite sides of the Pitot tube or orifice plate in themain steam pipe leading from the boiler. The pressure acts through themedium of a quantity. of mercury in a mercury pot F, as next. described.The mercury pot F consists of a cylindrical casing 50 mounted on abracket or hearing 51 fastened to the interior of the casing C by meansof screws 53. The casing 50 encloses a cylinder 54 in which is thepiston 55 having upper and lower pistonrods 56 and '57 sliding throughstufiing boxes 58 the upper rod 56 being further supported from abearing 59 carried by the arm 7 which braces the piston-rod 5. Thepiston 55 is normally maintained in raised position, as illustrated inFig. 2, by the mercury m in the pot 50, it being noted that the interiorof the pot communicates with the cylinder 54 through openings 60 at thebottom thereof. Steamis admitted to the top of the mercury pot F understatic pres sure through a nipple 61 entering its side and connectedwith a steam supply pipe to be later described. Steam. under velocitypressure is admitted to the top of the cylinder 54, in which the piston55 slides, through a port 62 into which is threaded a pipe 63 connectedby a pipe 64 leading directly from the Pitot tube to be later described.

, Piston comzvterwee'glzt. For counterweighting the piston 55 and itsattached parts I preferably employ a bell-crank lever- 70 fulcrumedat't'l on a bearing extending from the side of the casing C. The shortarm of the bell-crank 70 carries a pendant rod 72 having means at itslower end for supporting a plurality of weights 73 which may besubtracted or added to as required. The-long arm of the bell-cranlrTOterminates in a fork having slots 74 engaged by a crosspin '75 driventhrough theupper piston rod 56. As the bell-crank 70 is rocked under therise and fall of the piston 55 theleverage of its shorter arm will bevaried. to adjust the effect of the weights 73 in proportion as requiredto counterbalancethe piston and its parts under varying operatingconditions; this action being more fully described hereinafter. Thelower piston-rod 57 is conneoted to the steampressure operated pistonthrough a differential compensating mechanism or governor constructedand arranged as next described.

Di/ferential g0oera0r.-Betweenthe static steam-pressure control-memberor piston 20 and the velocity steam-pressure control-ole ment or pistonis a differential mechanism which constitutes the main gOV8l.1'llI1element of the apparatus. One form or this governor is illustrated inFig. 2 and shown in detail in Figs. 5 to 7. As here illustrated theupper end of the piston 26, which is operated from the steam pressurecylinder 40, is reduced in diameter to receive a flanged cup fastenedthereto by a. cross-pin 81. The lower end of the piston-rod 57, operatedfrom the piston 55, is also reduced in diameter to receive asimilarly-shaped inverted cup 82 held thereon by a cross-pin Suspendedfrom the'-"upper cup 82 is a differential weight which is constituted bya series of semicircular weightlinks 85 joined together by a novelarrangement of mechanism as next (lGSCllbGt. As shown in Figs. 5 and (i,the weights 85 consist of halfrings which are pivoted together by meansof wire pins 86 passing through hingedugs S7 and bent around at theirends to hold them in place. Each half-ring or weightlink 85 is providedwith a forwardly pro jecting lug 88 on its inner edge adjacent the jointwhich it makes with its complementary link, see the enlarged sectionalview, Fig. 7. The lugs 88 on each two opposite link-sections orhalf-rings are adapted toengage on opposite sides of a wire-staple 89which has its ends secured loosely in the opposite complementary links.The upper link of the series is fastened to the bottom of the upper cup82 by means of screws 90, see Fig. 5, and the distance between the cupsis proportioned that the lower link of the series will normally besuspended just above the bottom cup 80, see Fig. 2. All of the linkswill therefor be normally supported from the upper cup due to the factthat the play or swivelingaction at their hinges is limited by thedogging action of the lugs 88 on the cross wires or staples 89. In otherwords, the lugs 88 on each pair of links 85 pinch against the staple 89and prevent the links from being extended in the axial direction of thechainor helix formed by the series of connected links, see Figs. 6 and7. lVhen, however, the lower cup 80 rises in relation to the upper cup82 the individual links are successively picked up and the weight ofeach added to the lower cup while the remaining links hang suspendedfrom the upper cup, the functioning of this mechanism being explainedmore fully in connection with the operation of the complete apparatus.

Alternative form of ah'fiereniial gov-- ernor.A modified form of thedifferential governing-device is illustrated in Fig. 3 of the drawings,in which a single cylindrical weight is carried by the piston 20 andnormally held submerged in a bath of mercury contained in a jar 96suspended from the lower pistorrrod 57 of the piston 55. The rising ofthe pistion 2G, or the dropping of the piston alters the degree ofsubmergence of the weight 95 in the mercury in and thus varies itsoperative effect on the piston 26 in accordance with requirements. Forthis purpose the piston-rod 57 has an en larged extension 9'? at itslower end carrying an inverted cup 98, to which is attached acylindrical casing 99. The lower part of this casing 99 is formed with aflange 100, to which is attached the mercury jar 96by means of aninturned flange 101 at its top held by screws 102.

The upper part of the jar 96 is formed with a saucer-like rim 103 whichprovides an enlarged basin to add volume to the body of mercurycontained in the jar. This construction provides that as the weight 95rises out of the mercury in there will be a minimum change in the levelof the fluid. E tending upwardly from the bottom of the jar 96 above thelevel of the mercury contained therein is a cylindrical sleeve 10 1having a central bore through which the piston 26 slides with a loosefit. The upper end of the piston 26 is reduced in diameter to adapt itto slide into an axial bore 1.05 in the pistonrod 57, it being notedthat holes 107 are drilled through the rod 57 into its bore to allow theescape of air so that the movement of the piston 26 therein will not beresisted. The weight 95 is attached to the piston 26 by means of aflanged collar or cup 108. As shown in Fig. 3, the weight is fastened tot is flange by means of screws 109. and the collar or cup 108 is securedto the piston 26 by a cross-pin 110. lit will be seen that the weight 95is free to slide up and down within the mercury jar 98 without contactwith the sides thereof or with the bushing 1041. and the casing 99 isformed with openings 112 to permit the egress of air so as not to resistthe movement of the weight. The function of this moditied form ofdifferential compensating-device is the same as that previouslydescribed in which the connected weights are employed, its method ofoperation being hereinafter more fully explained.

The pressure comreozfe'ons.-For the static pressure and velocity headcontrol of the piston 55 I may employ a usual type of Pitot tube deviceas illustrated in Figs. 8 and 9. In these views the main steam pipe 115leading from the boiler is shown in section with the arrow a indicatingthe direction of {low therethrough. A nipple is inserted through theside of the pipe with a hand-valve 119 connecting it to a steam pipe117. Spaced-away fromthe nip- .ple 116 is a second nipple having an'up-V for'measuring the velocity head or flow of the steam. 9n the nipple118 is a hand-valvo 121 which connects with a steam pipe 122. Referringnow to Figs. 1 and 2, the pipe 117 for the static pressure leads throughthe top of the casing C down the side thereof, and is provided with a T128 which connects with the nipple 61 leading into the top of themercury pot l to supply pressure through the mercury to the under sideof the piston 55. The steam pipe 117is continued downwardly as indicatedat 124, to supply static pressure to the cylinder- P. a suitable fitting125 at its lower end being connected to the nipple 43 leading throughthe peoestal 41 to the bottom of the cylinder 40. The steam pipe 117,124 is continued horizontally across the bottom of the casing G andconnected to the motor M by means of suitable fittings 126, 127 and 128,the latter nipple leading into the steam-chest 14 on the side of themotor cylinder 2. lhe connections above described supply static pressureto the several steam cylinders; while the steam pipe 122 leads downthrough the top of the casing C and by means of an elbow 1230 con.necting with the nipple enters the duct 62 in the cylinder 50, thusproviding a velocity head acting against the top ofthe piston v55.

It will be understood that the steam connections may be varied asdesired and a modified fornr of steam flow device" employed in place ofthe Pitot tube. For example, in Fig. 10 I have illustrated a mod erntype of orifice plate, sometimes called a .Mexican'hat. lVith thisarrangement the main steam pipe 115 leading from the boiler is formed intwo flanged sections 135, 136, with'the orifice plate 137 held betweentheflanges thereof. lVith this construction a nipple 138 connectsthrough valve 139 and pipe 140 with the velocity side of mercury pot Fand a second nipple 141 valve 142 and pipe 143 connects with the staticside of the mercury pot.

Combustion c0mir0Za-ln the general view in Fig. 1 isshown an arrangementof my improved apparatus for regulating combustion in a conventionaltype of steam boiler furnace. It is to he understood, however, thatthisshowing is by way of example only, as the apparatus is adapted foruse with other types of furnaces and with different methods ofcontrol.In Fig. 1, B designates the boiler havingits furnace fed by an automaticstoker S which isoperated by a steam engine E taking pressure from theboiler through connections not herein illustrated and controlled by avalve 145. The valve lever 146 is weighted to normally hold it closedand is adapted to be opened by means of a cordfor chain 147 passing overa pulley 14 i A larger pulley 149 fast with the pulley148 has a chainl50 leading therefrom over a third pulley 151 and thence down to themain operating motor piston-rod 5 to which it is connected at 152.

The over fire or induced draft in the combustion chamber of thefurnaceis controlled by means of damper D in the main flue H. The damperD is moved from a lever 155 carrying a weight 156 at one end which tendstoholdit closed. Connected to the opposite end of the lever 155is a cordor chain 157 which forms a continuation of the chain 150 fastened to thepiston-rod 5. Through this arrangement the. dropping of the piston 4'will cause its rod 5 to open the lamper D.

In Fig. 1 I have also illustrated the furnace as provided with a forceddraft under the lire which is fed from a suitable blower or fanindicated at J as being operated from a steam turbine K. Pressure issupplied to the turbine motor K through asteam pipe 160 leading from theboiler and inwhich is a control valve 161. 7 The valve 161 is operatedfrom a weight-lever 162, the weight tending to maintain the valveclosed. Fastoned to the outer end of the lever 162 is a cord or chain163 leading up over apulley 164. The pulley 164 is fast wit-ha largerpulley 165 which has a chain leading thereover and connected to thechain 150 fastened tothe piston-rod 5. It will thus be seen that boththe overfire and under-fire drafts and the fuel feed are controlled fromthe movement of'the piston 5, and other controls may be added whenrequired. In place of the steam engines employed to 0p erate the StOlKGlS and the forced draft fan J, I may employ electric motors havingsuitable switches and rheostats for regulating the current through theoperation of controls from my improved apparatus In other caseswhereliquid fuel. is used in the. furnace, the supply to the burnernozzles may be controlled byvalves operated from the apparatus throughsuitable connection with the piston-rel The method of operation of thecomplete device is as followsj 1h ethod 0/ O ePat'z Om In Fig. 2 theseveral units of the apparatus are illustrated in convenient position torender the showing clear without regard for their normal cooperativerelation when the device is in use. The individual elements of themechanism may be proportioned and adjusted in ical condition. Forexample, assuming that the boiler is to operate at say 124- pounds gaugepressure, and that the constant weight 4 .5 on the piston 26 isproportioned to resist 120 pounds pressure in the cylinder 40, then withthe boiler at anything over 120 pounds the weight will be lifted ofi'its seat on the pedestal 41. Assuming further, that each of the hallcircular weights 85 of the differential weight-mechanism XV isproportioned to resist a hall pound of pressure in the cylinder 40, thenwith a static pressure in the boiler of 12st pounds the pressuresupplied :trom the main steam pipe 115 through pipes 117 and 124 tobottom of cylinder will cause the piston. 26 to raise the weight untilit is balanced. by eight of the onehalli pound weights 85; it beingunderstood that the piston 26 rises the cup on its upper endsuccessively picks up the ditferential weights to increase the operativeforce of the weight 45. As the piston 26 rises it lifts the long arm oflever 25 of the valve-gear V and slides the valve 10 to open the lowerport 18 in the steam-chest 14:, thus admitting steam to the bottom 01the cylinder 2 beneath the piston 41-. The pressure on the under sideoi? piston 4L raises the latter to slide its rod upwardly and by meansof the chains connected to the rod operates the control for the furnaceas follows:

Referring now to Fig. 1, as the piston-rod 5 slides upwardly the chain150 is paid out over the pulleys 151, 165 and 1419 with the followingresult: First, the flue-damper D is causedto be rocked into partlyclosed position under the action of its weight 156; second, thevalve-lever 146 is lowered to reduce the pressure to the engine Eoperating the automatic-stoker S; and third the lever ].(32 is alsolowered to reduce the pressure supplied through valve 161 to tin-brine Kwhich operates the forced draft tan or blower J.

It may be assumed that with the controls in position as shown in Fig. 1the boiler is operating under normal pressure with the constant weight.115 and. added differential weights 85 in the cup 80 balancing thepounds pressure in the cylinder &O. To maintain this condition, however,the piston 4i must be balanced and this is accomplished through. theaction of the valve-near V. As the piston ti rises its red 5 lifts thelong arm of lever 32, he short arm of which, operating through thereach-rod 30, depresses the fulcrum of lever 25, and in this way thevalve 10 is moved back into position to maintain the piston l balancedin the position it has previously assumed. Should the pressure in thebe" continue to rise, however, the continued upward movement of thepiston 26 will maintain the valve 10 open to admit steam to the underslde of piston 4c to slide its rod 5 upwardly until all of the controls,i. e., the fine damper D and valves and 161, are entirely closed.

Considering" the boiler as operating at normal, should the pressuretherein start to drop, for instance, from lowered combustion in thefurnace, the di'llerential weights 85 acting in conjunction with theconstant Weight 45 will cause the piston 26 to descend under thelessened pressure in the cylinder 40. This action will unseat the valve10 to admit steam at the top of cylinder 2 so that the pressure willcarry the piston 1 downwardly, thus causing its rod 5 to pull the chainto open the controls to increase combustion in the furnace.

The above explanation of the operation of the device takes intoconsideration only its action under control of static pressure, butindicates the general method of functioning; of the control actuator ormotor M and its valve-regulating means as constituted by theweight-controlled or differentially balanced pressure piston 26.Combustion control de- Vices operated under static pressure haveheretofore been employed in the art, but have not been foundsatisfactory and sutiicient for the purpose intended because of theirsluggish action. Slight changes in the condition or the fire may not beimmediately reflected in the boiler pressure and hence the controls willnot be operated promptly enough to increase combustion before thepressure has fallen to a considerable extent. Moreover, a suddenoverload on the boiler, as resulting from the starting of an additionalunit of machinery, will not immediately reduce the static pressure inthe boiler and hence the drain may be continued until it is too late tocheck the tall by opening the controls to increase combustion. these andother reasons it is therefore desirable to provide means for actuatingthe con trols under fluctuations in the steam flow or velocity head,which means will be more quickly responsive to an increase in the loadon the boiler. he present invention embraces such an improved control.of combustion under changes in steam flow or velocity head as effectedby certain elements of the apparatus above described, the novel methodof operation of which is as follows:

Gpemtioa under velocity head control.- Assuming that the boiler isrunning along at normal gauge pressure of 124- pounds with the parts ofthe control apparatus in balanced relation as above described, if a newunit of machinery started a heavy load is placed on the engine with asudden heavy demand for steam from the boiler. The creased demand forsteam from the boiler will instantly cause an increasedveloci yhead inthe steam main, which acting through the Pitot tube device or apertureplate and connections to inouce pressure on the piston 55 For of pistonwill therefore overcome its balance andforce the piston downward,causing its rod 57 to progressively deposit the differential weights 85on the cup 80 surmounting the piston 26; Thepiston 26 will thus beoverbalanced and forced downwardly against the pressure in the cylinder40, and during its motion it vill shift the lever to slide the valve 10to admit pressure at.

the top of the motor cylinder 2. Consequently, the piston 4 will becaused to descend to slide its rod 5'to pull the connecting chain 150,see Fig. 1, whereby to open the damper D and also the control-valves 145and 161 for the stolrer engine E and blower turbine K. Through thisaction comby the decreasing bustion in the furnace is immediatelyincreased until pressure in the boiler is raised to take care of theextra load. As the pre sure, in the boiler increases the piston 25 willbe raised again, and acting through the lever 25 it will operate thevalve- 4- V to balance the piston 4 in proper position to once moresetthe controls for normal com bustionin the furnace without waste offuel,

As the piston descends it'roclrs the bell v crank lever connected to itsrod 56 to ra se the counterweight-s 73, and as the bellcrank turns onlts pivot 71 the leverage of its short arm diminishes to reduce theoper- The bell-crank f 70 and its weights Z3 are so proportioned thatative force of the weights.

as the differential weights 85 are dropped from piston 55 into the lowercup on the piston 26 the loss of weight on the pieten 55 is compensated,or substantially so,

' on the bell-cranltTO. during its rocking mothe static andflow tion. Inthis way the piston 55 and its, connected parts are at all timesmaintained under an approximatebalance so that it will be more sensitiveto thecontrol of pressure from the Pitottube.

' It has been explained that theleads from sidesof the aperture plate137 in'the main steampipe 115, see 10, control the pressure on thepiston55 in the mercury pot F in til-.QSSIHQ manner to obtain the same resultwith the Pilot tube shown in Figsvl and 8; It i also to be understoodthatthe modified. formof differential-weight device shown in Fl 3, whichis the preferred form of this element, functions in substantially thesamemanner as the linked weights illustrated at'W in- Fig. 2. When theeffect of the weights I t3 piston 55 is forced down in the mercury pot Fthe mercury jar 96 will be lowered to lessen the degree of submergenceof the cylindrical weight on the lower piston 26. The operative'force ofweight95 on piston 26 is therefore augmented to cause the piston to beoverbalanced against .t-he pressure e'flicient in its control so thatconditions of combustion in the furnace are not permltted to varybetween wide extremes; In other words,the dev ce operates automaticallyto quirements of the load on the boiler or the steam flow therefrom, butnot toan extent to cause waste of'fuel by allowing the pressure to gettoo low and then increasing combustion to an abnormal degree. p While Ihave described and illustrated my invention as embodied in apparatus ofacertain structure it is to be understood that changes may be made in theform and arrangement of its parts beyond the modifications hereinsuggested, and such alterations in design and construction would fallwithin the scope and spirit of the invention as defined by the appendedclaims.

I claim: r

1. In a combustion-controlling device for steam boiler furnaces, thecomblnation of a pressure operated motor for adjusting the furnacecontrols, a balanced piston operative under static pressure from theboiler on'one sideand velocity pressure on the opposite side, adifferential governor operated from the balanced piston, and meansoperated by the movement of said piston and controlled by the action ofthe governor to control'the pressure in the motor to regulate itsadjustment of the furnace controls. 7

2. In adevice of the type specified, the combination with the controlsof a steam boiler furnace,'of a motor foroperating said controls, apiston displaceable by steam pres sure from the boiler under velocityhead,. a differential governor" connected to said piston, and meansactuated by said piston under the control of the governor to regulatethe action of the motorto operate the controls in accordance with theflucuations in steam flow from the boiler.

3. In a 'deviceof the type'specified, the

in the cylinder 40, whereby the piston will It will also be seenincrease combustion'in accordance with recombination of a motor foroperating the controls, of a steam boiler furnace, means to energize themotor to open and close the controls, a balanced piston displaceable bypressure under velocity head from the boiler, a differential governorconnected to said piston, and means operated by the piston under thecontrol of the governor to regulate the application of energy to themotor.

l. In a device of the type specified, the combination or a piston foroperating the controls of a steam boiler furnace, means for supplyingpressure to the piston to move it in opposite directions to open andclose the controls, a second balanced piston, a differential governorbetween the first and second pistons, means to supply pressure undervelocity head from the boiler to the balanced piston, and means operatedby the displace ment of the balanced piston a d acting through thedifferential governor to regu' latethe action of the cont-roloperatingpiston.

In a device of the type specified, the combination of a piston foroperating the controls of a stem boiler furnace, means for applyingpressure on opposite sides of the piston, a valve for controlling thedirection. of application of pressure on the piston, a second balancedpiston, a differential gravity operated governor connected to thebalanced piston, means for applying pressure under velocity head fromthe boilerto displace the balanced piston, and means operated by themovement of the balanced piston and controlled by the governor toregulate the action of the valve for the control-operating piston.

6. In a device of the type specified, the combination of a piston foroperating the controls of a steam boiler furnace, a va ve for admittingpressure to opposite sides oi said piston, a second piston operated bystatic prcr-isure from the boiler to shift the valve to admit pressureto the first piston to operate the furnace controls, a valve-gearopcratcd from the first piston to reset the valve to hold said piston inbalanced position, a third piston operated by steam pressure undervelocity, head from the boiler, and means operated from the third pistonto regulatc the movement of the second piston which controls the valvefor the first piston.

7. In a device of the type specified, the combination of a piston foroperating the controls of a steam boiler furnace, a valve for admittingpressure to opposite sides of piston, a second piston operated by ticpressure from the boiler to shift the valve to admit pressure to thefirst piston to operate the furnace controls, a valve-gear operated fromthe first piston to reset the valve to hold said piston in balancedposition, a third piston operated by steam pressure under velocity headfrom the boiler,

and diiferential mechanism operated from the third piston to resist themovement of the second piston after the latter has shifted the valve forthe first piston to a predetermined extent.

8. In a device of the type specified, the combination of a fluidpressure piston for operating the controls of a steam boiler furnace, avalve tor admitting pressure to opposits sides of said piston, a secondpiston operated under static pressure from the boiler to shift the valvefor the first piston, a counterweight for resisting the movement of thesecond piston, a third piston operated by pressure under velocity headfrom the boiler, and a diiiercntial governor-mechanism acting toautomatically increase and decrease the force of the Weight forresisting the movement of the second piston in accordance withfluctuations in steam flow from the boiler.

9. in a device of the type specified, the combination of a motor forshitting the furnace controls, beans for controlling the direction ofaction of the motor, a piston operated by static pressure from theboiler to operate the motor-controlling means, a

aveight acting against said piston, a balanced piston operated bypressure under velocity head from the boiler, and differential mechanismoperated by the movement of the balanced piston to increase and decreasethe Weight on the static pressure piston Whereby to regulate its controlof the motor under fluctuations in steam flow from the boiler.

10. In a device of the type specified, the combination of a fluidpressure cylinder, a piston in said cylinder, means for connecting saidpiston to shift the furnace controls, a valve for admitting pressure toopposite sides oi said piston, a second piston operated by staticpressure from the boiler, a counterweight on the static piston, meansconnectingthe static piston to operate the controlvalve for the firstpiston, a third piston operated by pro re under velocity head from theboiler, and a diiforential-governor operated from the third piston toapply a variable degree of We on the static-pis ton to regulate theaction'o't the latter in proportion to the increased steam flow from theboiler. i

11. In a device of the type specified, the combination of a motor forshifting the furnace controls, means for controlling the direction ofaction oi said motor, a" piston operated by static pressure from theboiler to actuate the 1notoiJ'-controiling means, a second pistonoperated by pressure from the boiler under velocity head, a mercury jarcarried by the second piston to adapt it to be raised and lowered by themovement of said piston, and a Weight on the first piston submerged inthe mercury in the jar carried by the second piston whereby movement ofthe second piston regulates the degree of submergence of said weight tovary its operative force on the first piston.

12. In a device of the type specified, the combination of a motortorshittingthe turnace controls, means for controlling the direction ofaction of said motor, a piston operated by static pressure from theboiler to shift the motor-controlling" means, a secondpiston operated bypressure under velocityhead from the boiler, a mercury suspended fromthe second piston and providcd with a sleeve through which the firstpiston slides, and a cylindrical weight sup' from the boiler undervelocity head, a mercury jar suspended from'the balanced piston andprovided with an opening in its bottom through which the static pistonslides, and a cylindrical weight surrounding the static piston andcarried thereby to adapt it to be submerged to a variable extent in themercury in the j ar carried bythe balanced piston in accordance with therelative displacement of said pistons.

14. In a device of the type specified, the combination with the furnacecontrols, of a motorfor operating said controls, means for controllingthe operation of .saidmotor, a mercury pot, a piston maintainedsuspended by the. mercury in said pot, means for admitting statlcpressure from'the boiler to hold the piston suspended, meansftoradmitting pressure under velocity head from the boiler to act againsttheopposite side of the piston, and means operated from the movement ofsaid piston to regulate the action of the motor-controlling means incordance with variations in'the flow of steam from the boiler.

15'. In a combustion-controlling; device for steam boiler furnaces, thecombination with the furnace'co'ntrols, of a fluid pressure cylinder, apiston. slldable 1n said cylinder and connected to operate the furnaceeontrols, a valve in the cylinder for controlling the admission ofpressure to opposite sides of the piston, a lever for shifting saidvalve, a second lever operated from the pistonan-d connected to thefirstlever to shift the fulcrum of the latter't-o re-seat the valve,

a second piston 'operatedby static pressure .eury to control theposition of the the chamber on one side of the piston, and

means for admitting steam under velocity pressure to the chamber on theopposite side of the piston :Wher by to operate the latter in the mannerand tor the purpose substantially as described.

17. In a combustion-controlling device for steam boiler furnaces, thecombinationot a cylinder containing a heavy fiuid,;a piston suspended inthe fluid in the cylinder, means for admitting steam under staticpressure to the cylinder on one side of the piston, and means foradmitting steam under velocity pressure to the cylinder on the oppositeside of the piston.

18, In a combustion controlling device for steam boiler "urnaces, thecombination of a cylinder containing mercury, a piston slid able in saidcylinder, and means for supplying'steam under velocity head to the interior of the cylinder to act against themerpiston in the cylinder.

19. In a combustion-controlling devicetor steam boiler furnaces, thecombination of a cylinder, a piston slidable in the cylinder. a chambercommunicating With the cylinder, a supply of heavy fluid in the chamberfor maintaining the piston suspended in the cylinder, means foradmitting steam under velocity pressure to the chamber to act throughthefiuid on one side of the piston, and means for admitting steam understatic pressure to the cylinder to act on the opposite side' of thepiston. V v I 20. In a device of the type specified, the combination ofa cylinder, a piston slidable in said cylinder, a chamber surroundingthe cylinder and communicating therewith at I one end thereof, aquantity of mercury in the chamber maintained at the same level in thecylinder, means'tor supplying steam to the chamber under velocitypressure to act through the mercury on one side of the piston,and meansfor supplying steam to the cylinder uneer static pressure to act againstthe opposite side of the piston. In testimony whereot Iafiix mysignature.

WILLIAM H. LARKIN, JR.

